Hi,
This is a 16 year old Kenmore washer. All the bells and whistles. 3 speed motor, deluxe solenoids with three hoses under the cabinet that need to be disconnected
before removing the cabinet. Got the idea??

Well, this machine works fine until it gets to spin. Then it starts, stops, starts, stops
repeatedly and keeps doing that.

I encountered this exact problem about 6 years ago and I can't for the life of me remember how it turned out.

I think I replaced the motor, then the timer and the problem persisted. Then I
never heard from the customer again. So, I never really found out what the cause
was.

Reach back into your archives please and pull out this problem and it's cause for me.
I've just got to know what causes this situation.

It turns on and off, on and off, on and off over and over again. It never gets up to
spin speed. Just starts for a second and stops for a second. Like a switch is being turned on and off quickly and repeatedly.

This answer is an absolute long shot.... I had this similar call 2 months ago and I all did was move speed selector switch around(knob that designates delicate"slow spin-agitate" or heavy duty"fast agitate and spin") The knob was actually stuck between cycles.I am sure I will never get that lucky again but give it a shot.

Need to see if there is voltage to the motor or not when it is cutting in and out, if so could be a bad motor, if not trace back to see where the voltage is getting lost, could be as simple as bad connections at where the harness plugs onto the motor switch or a bad spot in the harness. Sounds like voltage is being lost somewhere in the spin cycle but not the Agitate cycle? Focus on the spin wiring...in the wiring, connections and motor terminals.

im not sure if this will help you or not. it is a 3speed whirlpool machine i traced out some time ago. I dont know if its the same as your machine but you will have to trace power to the run winding as it sounds like the motor is recieving power to the start but not the run.

on the wireing diagram there will be a chart that shows which terminals are closed in each position. you may find 2 closed when only one should be. but first rotate the switch back and forth several times and try it agian.